Inhibition of nuclear factor κB by IκB superrepressor gene transfer ameliorates ischemia-reperfusion injury after experimental lung transplantation

Objectives: Ischemia-reperfusion injury after lung transplantation is associated with significant morbidity and mortality. The activation of the transcription factor nuclear factor κB is central to the 2 important pathways that characterize ischemia-reperfusion injury, namely the inflammatory response and apoptosis. The purpose of this study was to determine the effects of nuclear factor κB inhibition on experimental lung transplant ischemia-reperfusion injury with gene transfer of the nuclear factor κB inhibitor IκB in a superrepressor form (IκBSR). Methods: An orthotopic left lung transplant model in isogeneic rats was used, with 18 hours of prolonged cold storage of donor lung grafts used to create severe ischemia-reperfusion injury. Donor rats underwent endobronchial gene transfection with saline alone or adenovirus encoding either β-galactosidase control or IκBSR 48 hours before harvest. The function of transplanted lung grafts was assessed on the basis of isolated graft oxygenation, wet/dry lung weight ratio, and myeloperoxidase activity. Nuclear factor κB activation was assessed by means of enzyme-linked immunosorbent assay. Apoptotic cell death was assessed by evaluating the levels of histone-associated DNA fragments and caspase-3 activity. Results: Treatment of donor lung grafts with IκBSR resulted in significantly improved oxygenation compared with that seen in control tissue 24 hours after transplantation. IκBSR-treated lungs also demonstrated less pulmonary edema and reduced neutrophil infiltration 24 hours after reperfusion. Nuclear factor κB activation and apoptotic cell death induction 2 hours after transplantation was significantly reduced in IκBSR-treated lungs compared with in control lungs. Conclusions: Inhibition of nuclear factor κB activation by IκBSR gene transfer improves transplanted lung graft oxygenation, decreases pulmonary edema and neutrophil sequestration, and reduces apoptotic cell death after experimental lung transplantation.